Does free particle possibly self-interact?

[ndung200790]

Energy-momentum conservation law forbid free particle radiates.Then does free particle possibly self interact by emiting and absorbing virtue gauge boson particles?Is there a classical static field caused by ''virtue radiation'' surrounding the particle?

Is the origin of mass of fermions to be the self-interaction energy(saying above)(example electron mass is the energy of interacting between electron and static electric field cause by it?) or by Higg mechanism or by both?

If we consider many symmetries at a same time,how can we construct covariant derivative?Because we must consider many types of gauge field boson at a same time.

 

[tom.stoer]

There is self-interaction and this self-interaction indeed affects the masses, but all these processes are subject to renormalization, so the renormalized masses must always match the observed masses.

I am not familiar with renormalization of self-energy diagrams in the presence of Higgs fields, but the situation w/o Higgs fields is well-known: you tune the renormalization such that the correct masses come out. In case of massless particles like photons this means that the contribution of the self-interaction to the total invariant mass must vanish.

 

[ndung200790]

How about the Lagrangian that satisfies many symmetries?Weak interaction and electromagnetic interaction ''interfere'' each other(example W bosons can interact with photons).How about the interference between strong interaction and electroweak interaction?How can we construct the Lagrangian of SU(3)xSU(2)xU(1)(in case particles interact through all three forces) from QCD Lagrangian and electroweak Lagrangian?

 

[ndung200790]

It seems that the Standard Model says nothing about whether SU(3) and SU(2)xU(1) are ''isolated'' with each other or not.If there is a ''interference'' between SU(3) and
SU(2)xU(1) we have a ''unifying'' in the theory and we can write SU(3)xSU(2)xU(1),otherwise the SU(3) and SU(2)xU(1) are ''independent'' and therefore the total Lagrangian is a simple sum of SU(3) Lagrangian and SU(2)xU(1) Lagrangian.

 

[tom.stoer]

In the standard model the different SU(n) groups come w/o any relation between them.